Adding high-intensity intervals to workout may yield better results

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Moira Jrolf, center, pictured with Kelly Tierney, left, and sister Tara O'Leary, completed the Sharon's Back Triathlon in Sharon, Mass., in August 2008. Jrolf, 41, says she's more toned and less bored with exercising since incorporating short-burst interval training into her routine.

Since shaking up her fitness routine, Moira Jrolf is spending less time exercising yet getting better results.

She used to focus just on long periods of sustained physical activity — such as an hour-long run or 1.5 hours of nonstop lap swimming — but over the last couple of years she’s been incorporating short-burst interval training into her fitness regimen. She does sprints at the track or in the pool, for instance, with rest periods in between. But those brief breaks are more than made up for by the high intensity of her sprints.

“It definitely is good to mix it up because you feel like you’re really pushing your limits with the interval workouts,” says Jrolf, 41, of the Boston area.

And, says the busy mother of four young children, “On the days I do my interval training, the workout is shorter, so I put in less actual time working out.”

When going full speed ahead, one just can’t sustain the activity for as long. “On the days I do the interval training, I save about 20 to 30 minutes per workout,” she says. So instead of lap swimming for an hour and a half at a stretch, she takes an hour-long interval-based swim class. And one of her three running days each week involves 30 to 40 minutes at the track doing sprints rather than a slower, hour-long run.

The approach has paid off. Since Jrolf started interval training, she says she’s become more toned, faster and much less bored while exercising. Last April, she completed her first marathon.

Short-burst interval training — often with 15-, 30- or 60-second bouts of all-out activity followed by a brief recovery period — has long been a part of the regimen for elite athletes. And now, fitness professionals say, it’s gaining popularity with recreational exercisers who are tired of their usual, monotonous endurance workouts and looking for ways to save time.

A recent article in the trade journal for fitness instructors and other professional members of the IDEA Health and Fitness Association highlighted short-burst training as a “new frontier” in the fitness field.

The message: If you feel guilty when you stop in the middle of a workout for a break, don’t. Taking a series of breaks while working out may even help you get better results, faster — provided you work really hard in between those pit stops.

Less time, greater intensity
“Despite the low time commitment, we’re showing many of the benefits that people associate with traditional endurance exercise,” says Martin Gibala, chair of the department of kinesiology at McMaster University in Hamilton, Ontario, who studies short-burst training.

For instance, Gibala and colleagues published a small study last year finding that people who did short-burst training for a total of 1.5 hours a week (including rest periods) achieved the same exercise-induced changes in their muscles over six weeks as people who did more traditional endurance training for upwards of 4.5 hours a week.

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Still, Gibala and other experts say, more and longer research is needed to determine if short-burst training yields all of the same health benefits, without added risks, as traditional endurance training.

And just because the exercise involves less time doesn’t necessarily mean it feels better.

“It’s nice to talk about getting away with very little exercise, but those short bursts hurt,” Gibala says.

But with high rates of obesity and other health issues in the general population, he says, high-intensity interval training may not be for everyone.

“There will always be a significant audience who does not enjoy this type of training and will find milder, gentler and less intimidating exercise to be more motivating and simpler to incorporate into their day,” says Blahnik. He recommends people experiment with a variety of training styles to see what they like — and will actually do.

Talk to your doctor
Couch potatoes who are considering short-burst training shouldn’t go too far too fast, cautions Dr. William Kraus, a cardiologist and professor of medicine at Duke University Medical Center in Durham, N.C. Kraus was a member of the committee that advised the federal government on the physical activity guidelines released last year.

“In the report on which the guidelines are based, we advised that starting a program with moderate-intensity activity — for example, brisk walking — would be associated with little risk, but starting a program with vigorous activity might be potentially hazardous.” Risks could include a range of physical injuries and even sudden cardiac death.

Gibala recommends that exercisers check with their doctor before starting any new physical activity program. Once they have the go-ahead, one way to begin short-burst training is to speed up a bit on the treadmill, getting “out of your comfort zone” for a minute, then scaling back or stopping for a minute, then doing another short burst, for a total of 10 intervals. As your fitness level improves, you can challenge yourself more.

No doubt short-burst training can be tough, but people like Michael Melvin relish the challenge.

Up until about a year ago, Melvin, 30, who works in sales, spent most of his gym time on strength-training machines. But at 5 foot, 7 inches and 240 pounds, he was overweight and needed a change.

So he started taking a boot camp-style class at Catz Sports Performance Center in Wilmington, Mass., where he spends the same amount of time working out as before, generally four or five days a week, but is getting more muscular and losing weight — 50 pounds in the last year. The class incorporates intervals of various activities, including sprints and calisthenics.

“I’ve noticed dramatic results in a lot less time,” he says.

He’s also gotten more serious about dietary change. “I can’t have a cheeseburger at lunch and come here and perform well at all,” he says. “It’s almost like you have to stick to your diet.”

A key factor to his fitness success is that he doesn’t get bored like he did with traditional endurance activity.